When Doctor Who premiered in 1963, the BBC probably didn't anticipate it becoming a worldwide phenomenon and the longest-running science-fiction show in history.

The BBC finally completed the story-with new effects, a score, and linking narration by Baker-and six shortened episodes were given a 111-minute VHS release in 1992.

Almost forty years later, though, the cast of the story have been reunited and chief among them is Tom Baker, the Fourth Doctor himself who played the role from 1974-1981. More recently, though, Baker played a mysterious character known as the Curator in 2013's "The Day of the Doctor". Worldwide wasn't content to have the episode lost forever, using an animated sequence to help fill in the gaps, in addition to filming a new scene with Baker. Unfortunately, strikes wracked Britain for months and the episode was put on the backburner, with some of the existing footage later used in the Doctor Who 20th anniversary special.